<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div.father{
            width: 400px;
            height: 2000px;
            background-color: lightgray;
            position: absolute;

        }
        div{
            width: 100px;
            height: 100px;
        }
        .d1{
            background-color: red;

        }
        .d2{
            background-color: yellow;
            position: absolute;
            left:100px;

        }
        .d3{
            background-color: green;

        }
        img{
            position: fixed;
            right: 20px;
            bottom:100px;

        }
        .d4{
            opacity: 0.5;
        }

    </style>
</head>
<body>
<div class="father">
<div class="d1"></div>
<div class="d2"></div>
<div class="d3"></div>
</div>
<div class="d4">
    你好你好娃哈哈
<img src="timg.jpg" alt="">
    </div>
</body>
</html>